Documentation

Edit Bus

8 min read

Used in a Schematic Design to edit an existing Bus.

Shortcuts

Default Keys: None

Default Menu: None

Command: Edit Segment

Mouse: Double Click on bus segment

Locating this option

Available from: Context menu > Edit Segment option

How To Enter Edit Bus Mode

Edit Bus mode can be entered in a number of ways as follows:

  • Use Insert Bus to start a bus. Pick a connectable item, and you are then placed into Edit Bus Mode.
  • Double Click on an existing bus segment. Edit Bus will be entered adding bus segments starting from the end of the picked item closest to the picked position.
  • Select a single bus segment and right click to use the Edit Segment command from the shortcut menu.

How To Edit A Bus

Whilst in Edit Bus Mode you are performing one of the following two actions, which will be referred to later:

  • Editing a bus segment - Trailing Dynamic segment(s) are drawn from the moving cursor position to the target finish point. i.e Back to the end of the original segment you were editing.
  • Adding a new bus - There is no target finish point, so no trailing item is drawn.

The general method of adding bus segments is as follows:

  1. Move the cursor to position the dynamic segment attached to it. If two segments are dynamic then concentrate on positioning the first of them, i.e not the one attached to the cursor. The Status bar will show details about the segments being moved.

  2. Left Click in space to add a corner and commit each bus segment in turn. If a finish item is close to the cursor, but you do not want to finish on it you can use Shift Left Click to force a corner.

  3. Right Click to use the shortcut menu to alter the bus appearance, alter the editing preferences, change the segment being edited, and cancel or finish the bus. These options are described in more detail below.

  4. Press the Escape key to cancel the Edit Bus mode at any time.

  5. Left Click over an item to finish the bus on that item. This is only available when adding a new bus, or are adding new segments at the end of an existing bus. You can finish the bus on another bus segment to create attached busses representing the same signals, or you can connect it to a block terminal or port to take the bus down through a hierarchical design.

    If you are joining two busses you will be warned if this action will result in one of them changing its name or net names to be the same as the other. You can only join two busses if they are compatible as follows:

    • If both are named they must have the same name.
    • If any are open busses, they must not have connections attached.
    • If only one is named, the other must have a set of net names that are a subset of the nets on the named bus.If two unnamed closed busses are joined with incompatible net names, you will be warned and they will both end up with the same superset of the net names.

  6. Left Double Click in space to finish the bus at the picked position.

Edit Bus Options

During the Edit Bus process Right Click to use the shortcut menu:-

You may then select from a number of options:

Cancel

Use this to cancel the Edit Bus or Insert Bus operation.

Exit This Mode

This is available if you are inserting a new bus. Use it to cancel insertion of the current bus and exit directly back to Select Mode.

Finish Here

Use to finish the bus at its current position. The dynamic segments are added to the design and if there is a trailing connection or bus segment(s), these too are added to the design as seen.

Type Coordinate and Type Offset

It is possible to position the current corner by typing a position into a dialog, rather than clicking with the mouse. See the Type Coordinate help page for details on using this dialog.

Change Style

Use to change the current width of the dynamic bus segments, or to change the complete bus to a new width. This enables you to ‘neck’ bus to fit through small gaps and to ‘fatten’ bus again at the end of these gaps. See the Change Style help page for more details.

Change Bus

Use to change the bus being edited to use the bus name and set of allowed nets from another closed bus in the design. This option is only available if the bus and any other bus joined to it, have no connections attached to them. The bus name or description of the allowed nets is shown on the Status Bar. See the Change Bus help page for more details.

End Bus On

This sub-menu is available when adding a new bus in a block. It allows you to end the moving bus segment at the cursor position on a Bus Reference or a Block Port.

The Insert Doc Symbol dialog is displayed to choose a doc symbol to use for the bus reference or block port. For a block port, a unique port name will be allocated by the system and attached to the doc symbol’s pin. Bus Reference and Block Port symbols are created as a type of Documentation Symbol.

The symbol is added to the design and attached to the cursor, ready to be positioned.

Disconnect Bus End

This option is only available if you are editing an existing bus segment. Use it to disconnect one end of the bus you are editing from the item it was attached to. You are then switched to be adding new segments at the end of the bus you disconnected. So you are now in adding new bus mode and can therefore finish the bus end on another item.

The end of the bus that gets disconnected is either the start if you are editing the first segment, or else the segment at the end of the bus. But if the bus is only attached at one end then this is always the end that gets disconnected.

Editing Options

Presents a sub-menu containing alternative bus characteristics and editing preferences:-

(The list below is shown as a brief overview to the functionality, a full description can be found on the relevant page):

Auto Corner - Allows you to automatically insert corners by moving the cursor perpendicular to the current bus direction. This will then add a corner and allow you to continue routing without clicking the left mouse button.

Orthogonal Mitre - When adding corners (manually or automatically) you can set this option so that the Mitres or Fillets are always added to any 90 degree corners.

Curved Mitre - Only available when Orthogonal Mitre is enabled. Use this to choose between using angled mitres or curved fillets.

Apply Segment Mode To Tail

  • Only available if editing an existing bus segment, so that you have a trailing dynamic segment. Use so that when you do Finish Here, you do not end up with angled segments.

Change Segments

Presents a sub-menu containing alternative segment preferences:-

(The list below is shown as a brief overview to the functionality, a full description can be found on the relevant page):

Segment Mode - Use to change the Segment Mode using another shortcut menu. Choose between adding orthogonal, angled, curved or free angle segments.

Edit Segment - Use this sub-menu to change which segment you are editing.

Flip Dynamic Segments - When using a segment mode showing two dynamic segments, use this option to swap the type of the two segments over. For example, from XY mode to YX.

Delete Segment - Use to remove the segment previous to the one you are currently editing. This way you can ‘un-stitch’ the previous segments you have added in order to add them again in different positions.

Reverse Edit Direction - Only available if you are editing an existing bus. Use it to change the direction you are editing by reversing the bus. So the bus start becomes the bus end and vice-versa.

Change Grid

This sub-menu allows you to choose which grid you wish to force the bus segments on whilst adding them, if any. It also allows you to change the grid step and whether the grids are visible or not. See the Change Grid help page for more details.

Auto Corner | Bus Properties | Change Bus | Change Style | Grids | Insert Bus | Mitre | Segment mode | Status bar | Technology | Type Coordinate

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